The diving behaviours of marine predators are thought to be coupled with species demographics. Species that forage at or close to their physiological limits will be limited in their ability to respond to natural or anthropogenic induced changes in their environment. This is the case for the New Zealand sea lion (Phocarctos hookeri). A previous study from Enderby Island, Auckland Islands, the third largest colony for the endangered species, showed lactating females exhibit extreme diving behaviour, and that individuals have either: a benthic diving ecotype or a deeper, more varied mesopelagic diving ecotype which are maintained throughout their adult life. The ecological significance and implications for individual foraging specialisation has major consequences for this species as mesopelagic foragers are more likely to suffer mortality from fisheries than benthic foragers. We investigated the diving behaviour of lactating females from Dundas Island, Auckland Islands, the largest breeding colony for New Zealand sea lions. The diving behaviour of 24 lactating females was examined and confirmed that both diving ecotypes exist and that females at this colony are also operating at the upper limit of their physiological capability. Enderby and Dundas Island are the largest breeding colonies for the New Zealand sea lion and together represent 69% of this species pup production. This population has significantly declined since 1998, predominantly due to direct and indirect fisheries interactions. Measurable conservation and management steps are therefore critical to mitigate the impacts of fisheries on this population.

中文翻译：

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在新西兰最大的海狮群 Phocarctos hookeri 进行雌性极限潜水

海洋捕食者的潜水行为被认为与物种人口统计数据有关。在或接近其生理极限觅食的物种对自然或人为引起的环境变化做出反应的能力将受到限制。新西兰海狮（Phocarctos hookeri）就是这种情况。奥克兰群岛恩德比岛是濒危物种的第三大栖息地，此前的一项研究表明，哺乳期雌性表现出极端的潜水行为，并且个体具有：底栖潜水生态型或更深、更多样化的中层潜水生态型他们的成年生活。个体觅食专业化的生态意义和影响对该物种具有重大影响，因为中层觅食者比底栖觅食者更容易因渔业而死亡。我们调查了新西兰海狮最大的繁殖地奥克兰群岛登打士岛的哺乳期雌性的潜水行为。对 24 只哺乳期雌性的潜水行为进行了检查，证实了两种潜水生态型都存在，并且该群体的雌性也在其生理能力的上限下活动。恩德比岛和登打士岛是新西兰海狮最大的繁殖地，占该物种幼崽产量的 69%。自 1998 年以来，这一数量显着下降，主要是由于直接和间接的渔业相互作用。